22 December 2011

Solar Paint That Can Generate Electricity

Researchers at the University of Notre Dame has created an inexpensive “solar paint” that uses semiconducting nanoparticles to produce energy.

“We want to do something transformative, to move beyond current silicon-based solar technology,” says Prashant Kamat, John A. Zahm Professor of Science in Chemistry and Biochemistry and an investigator in Notre Dame’s Center for Nano Science and Technology (NDnano), who leads the research.

“By incorporating power-producing nanoparticles, called quantum dots, into a spreadable compound, we’ve made a one-coat solar paint that can be applied to any conductive surface without special equipment.”

They focused on nano-sized particles of titanium dioxide which were coated with either cadmium sulfide or cadmium selenide. The particles were then suspended in a water-alcohol mixture to create a paste. When this paste was brushed onto a conducting material and exposed to light, it created electricity.

The solar cell is easy to assemble because the middle layer can be painted onto a clear electrode. T-butanol, water, cadmium sulfide and titanium dioxide is mixed for thirty minutes. A clear electrode is masked off with office tape. Once the tape is in place, the mixture is spread onto the electrode and annealed with a heat gun. Afterwards, an electrolyte solution is sandwiched between the new electrode and a graphene composite electrode. Once this is done, the solar cell is ready for testing under a beam of artificial light.

Video: Painting Solar Cells with Nanoparticle Paste

Their research is described in the journal ACS Nano.

The best light-to-energy conversion efficiency we’ve reached so far is 1 percent, which is well behind the usual 10 to 15 percent efficiency of commercial silicon solar cells,” explains Kamat.

“But this paint can be made cheaply and in large quantities. If we can improve the efficiency somewhat, we may be able to make a real difference in meeting energy needs in the future.”

“That’s why we’ve christened the new paint, Sun-Believable,” he adds.

“Kamat and his team also plan to study ways to improve the stability of the new material.

NDnano is one of the leading nanotechnology centers in the world. Its mission is to study and manipulate the properties of materials and devices, as well as their interfaces with living systems, at the nano-scale.

This research was funded by the Department of Energy’s Office of Basic Energy Sciences.